There is a general agreement that during development the extracellular environment plays a critical role in controlling cell differentiation. However the exact factors responsible for promoting cell differentiation remain to be elucidated. Data generated from numerous studies support the possibility that candidates for this role (including differentiation of cells during cementogenesis), are cell attachment proteins and their corresponding cell receptors. The hypothesis upon which this proposal is based is that cell attachment proteins and their corresponding receptors are expressed in a unique fashion during cementogenesis. We predict that a precisely timed expression of these proteins in critical to the process of cementum formation. Specifically, the studies detailed in this proposal are directed at cementum formation. They will identify and characterize attachment proteins associated with cementum and their corresponding receptors and determine their expression during cementogenesis. While significant advances have been made in understanding dentinogenesis and amelogenesis, limited information has been obtained on the factors regulating cementogenesis. The major objectives of these studies are to 1) identify and characterize cell attachment proteins associated with the extracellular matrix of cementum; 2) determine in developing systems (in vivo and in vitro), the spacial and temporal localization of these proteins, pre and post cementogenesis, using immunological and nucleic acid probes; and 3) identify and characterize receptors for these proteins from periodontal derived fibroblasts and determine their expression during molar root formation. These studies will provide information on the role of attachment proteins and their corresponding receptors during cementogenesis. The information obtained from these studies may permit new and improved clinical periodontal treatments that could greatly diminish the effects of periodontal disease. For example, proteins may be identified that when applied to root surfaces will induce cell differentiation and/or cell attachment and subsequently periodontal regeneration. Moreover, this research will generate new knowledge on the factors regulating tissue development.